254 BULLETIN OF THE BUREAU OF FISHERIES. 
The imagos are found in large numbers around the ponds, but stick to the vegetation and do not 
fly out over the water. The nymphs were found in all of the ponds; and nymphiskins were present 
in all the counts. 
SYMPETRUM CORRUPTUM (Hagen). 
Mesothemis corrupta Hagen, Synop. Neurop. N. A., 1861, p. 171. 
Appears early in the season and is common around the ponds; then diminishes gradually and by 
the middle of August entirely disappears. 
Nymphs were found in all the ponds, and nymph skins occurred in the first two counts. It is the 
largest species of the genus and the strongest flyer, going out, like other dragonflies, over the water, 
but never in numbers, and remaining but a short time. 
ERYTHEMIS SIMPLICICOLLIS (Say). 
Libellula simplicicollis Say, Jour. Acad. Nat. Sci., Phila., 1839, p. 28. 
Second in abundance at the ponds, sticking close to the grass and weeds and never taking long 
flights. It does not perch on the sides of the grass stems like L. Iuctuosa, but prefers a horizontal blade 
of grass and settles down flat upon it. The females hunt almost exclusively in the grass and feed upon 
diptera, small butterflies and moths, and damselflies, especially teneral Enallagmas and Lestes (Pl. 
LXIX, fig. 2.) 
Williamson (1899, p. 326) has noted a peculiar habit of the males. Two of them hover over the 
surface of the pond close to the water, one a few inches above and in front of the other. The lower 
one then rises in a curve over the back of the upper one, which at the same time moves in a curve down- 
ward, backward, and then upward, so that the positions of the two are exactly reversed. ‘The two keep 
this up for several minutes and then separate; stich movements may be witnessed on any clear day 
by watching for it. 
The two sexes never fly about together, but the female oviposits alone, hovering close to the water 
and repeatedly dipping the tip of the abdomen beneath the surface. Both sexes alight on the floating 
alge and other water plants, unlike most dragon flies. 
The nymphs never crawl far from the water to transform, and many of the skins are found upon 
rush stems standing in the water. They showed a curious preference for Carex stricta and Homalo- 
cenchrus oryzoides, and but very few skins were found on other plants. Such a preference was probably 
due more to the position of the plants than to any other factor. The two sexes are shown in Plate 
LXIX, figure 1. 
PACHYDIPLAX LONGIPENNIS (Burmeister). 
Libellula longipennis Burmeister, Handb. Entomol., vol. 2, 1839, p. 850. 
Not very common around the ponds, although a few can be found there all through the season. 
The matured, pruinose males are more in evidence than the females; both sexes have the habit of droop- 
ing the wings and elevating the abdomen when they alight. Nymphs were more abundant in ponds 
2 and 3, and nymph skins more numerous in July and August. 
LIBELLULA LUCTUOSA Burmeister. 
Libellula luctuosa Burmeister, Handb. Entomol., vol. 2. 1839, p. 861. 
This is by far the most common species at Fairport and can be recognized by the broad, black 
bands across the wings, with chalky white spots outside of them in the male. It is very energetic and 
active, but alights often upon the grass and sedges and sometimes remains at rest a long time. It does 
not hover after the manner of some species and does not hunt late at night, being rarely seen actively 
flying about after sunset. It roosts in the tall grass up in the fields, holding onto the grass stem well down 
out of sight, and sometimes in the vegetation alongside of the ponds. Its characteristic attitude is to 
grasp the stem with all six legs, the longer hind legs holding the body inclined at an angle of about 45° 
with the stem, as shown in Plate LXVIII, figure 2. It gets thoroughly wet with the dew during the 
night and does not start flying in the morning until the dew has dried off. 
The two sexes do not fly about together after the manner of Anax, Tramea, and Celithemis, but the 
female oviposits alone, dropping her eggs loosely in the water, and not inserting them in the tissue of 
any water plant. 
